Apple support page discusses iPhone performance management, throttling options in iOS 11.3...

Posted:
in iPhone edited February 6
Apple has published a new page about lithium ion batteries in an iPhone, discussing how they work in simple terms, why throttling is necessary, and how iPhone performance management works in iOS 11.3.




On the new page, published on Tuesday, The company leads with a discussion about how the chemical aging process in a battery affects the power that can be supplied to an iPhone. While the company didn't delve too deeply into the physics and chemistry of a battery, it explains that voltage drops are responsible for a shutdown that are "intentional from the device perspective, but "unexpected by the user."

Apple clarifies that the feature is present in nearly all devices, with the most noticeable management in the iPhone 6, iPhone 6 Plus, iPhone 6s, iPhone 6s Plus, iPhone SE, iPhone 7, and iPhone 7 Plus. The company notes that the iPhone 8, iPhone 8 Plus, and iPhone X use a more advanced design for better estimation of power needs, allowing for a different management system -- making any throttling less noticeable on the new devices.

Performance management works by looking at a combination of the device temperature, battery state of charge, and battery impedance, and is only implemented if the variables require the throttling in order to prevent shutdowns.

Features of the iPhone affected by the throttling include:
  • Longer app launch times
  • Lower frame rates while scrolling
  • Backlight dimming (which can be overridden in Control Center)
  • Lower speaker volume by up to -3dB
  • Gradual frame rate reductions in some apps
  • During the most extreme cases, the camera flash will be disabled as visible in the camera UI
  • Apps refreshing in background may require reloading upon launch
Specifically not impacted by performance management are cell quality, networking performance, photo and video quality, GPS performance, location accuracy, sensors, and Apple Pay.

Apple does remind users that batteries are consumables, and have a "limited lifespan," necessitating replacement.

Battery Health beta

The new beta has the toggle switch that Apple CEO Tim Cook promised in January, to prevent the performance management from executing. It is only selectable after the first time the phone has throttled itself because of power demands.

The first time that the phone is throttled, the iPhone will explicitly warn the user in the Battery Health settings menu.
This iPhone has experienced an unexpected shutdown because the battery was unable to deliver the necessary peak power. Performance management has been applied to help prevent this from happening again.
Once toggled off, performance management cannot be turned back on. It will be turned on again automatically if an unexpected shutdown happens while the feature is disabled, and the user will have to select it again.

However, Apple notes that "fundamental performance management" such as behavior in hot or cold temperatures, or "internal voltage management" cannot be turned off for safety and functional reasons.

The new feature warns the users is the battery health is degraded so far, that users are likely to experience "noticeable battery and performance issues." If iOS cannot determine the battery health because of a non-Apple official battery or damage, it will also warn the user that the battery should be serviced.

Comments

  • Reply 1 of 11
    mytdavemytdave Posts: 429member
    Wish they would have made this feature into a 3 position slider in Battery Settings, so the user could choose the level of throttling, like this: Performance Management: Off, Mild, Aggressive. Not letting the user turn the feature on/off but requiring the phone to have an unexpected shutdown to re-enable management is obnoxious.
    pascal007
  • Reply 2 of 11
    mytdave said:
    Wish they would have made this feature into a 3 position slider in Battery Settings, so the user could choose the level of throttling, like this: Performance Management: Off, Mild, Aggressive. Not letting the user turn the feature on/off but requiring the phone to have an unexpected shutdown to re-enable management is obnoxious.


    This would be a perfect recipe for disaster.

    If they had a 3-position slider, how would you quantify "Mild" or "Aggressive"? Even the slightest bit of ambiguity would lead to class action lawsuits by law firms who are always on the prowl.

    There is nothing ambiguous about "On" and "Off" - it's either managing the performance, or not. It's much more straightforward.

  • Reply 3 of 11
    Rayz2016Rayz2016 Posts: 3,151member
    mytdave said:
    Wish they would have made this feature into a 3 position slider in Battery Settings, so the user could choose the level of throttling, like this: Performance Management: Off, Mild, Aggressive. Not letting the user turn the feature on/off but requiring the phone to have an unexpected shutdown to re-enable management is obnoxious.
    Veeeeerrry interesting. 

    When I first heard about this toggle thing, I voiced a concern that it may be possible to lose data or even damage the phone if it is constantly shutting down because of a stale battery. I was also concerned that Apple wouldn’t know if a user complaining of a bricked phone had deliberately switched off the performance management. If they permitted constant toggling then it would be much harder to ascertain if a damaged phone was down to a problem with the phone, or the user preferring the phone to crash instead of slowing the processor temporarily.

    Will be interesting to see how Apple views the warranty if they know you deliberately requested a phone crash when given the choice. 
    edited February 7
  • Reply 4 of 11
    jumejume Posts: 133member
    I wonder where are now all the fan boys that stated this would be the most stupid idea for Apple to implement and would destroy user experience?

    Thanks god for users complaining, law suits filling. Result, better UI control and experience. Well done Apple. 
    edited February 7
  • Reply 5 of 11
    Rayz2016Rayz2016 Posts: 3,151member
    jume said:
    I wonder where are now all the fan boys that stated this would be the most stupid idea for Apple to implement and would destroy user experience?

    Thanks god for users complaining, law suits filling. Result, better UI control and experience. Well done Apple. 
    I’m still here, and I still think it’s a stupid idea. 

    Fortunately, it’s not as big a disaster as I thought. They’ve prevented people from toggling endlessly, and the “feature” is for the 7 series down to the 5. It won’t appear on future models by the looks of it. 
  • Reply 6 of 11
    Rayz2016Rayz2016 Posts: 3,151member

    mytdave said:
    Wish they would have made this feature into a 3 position slider in Battery Settings, so the user could choose the level of throttling, like this: Performance Management: Off, Mild, Aggressive. Not letting the user turn the feature on/off but requiring the phone to have an unexpected shutdown to re-enable management is obnoxious.


    This would be a perfect recipe for disaster.

    If they had a 3-position slider, how would you quantify "Mild" or "Aggressive"? Even the slightest bit of ambiguity would lead to class action lawsuits by law firms who are always on the prowl.

    There is nothing ambiguous about "On" and "Off" - it's either managing the performance, or not. It's much more straightforward.

    Indeed. Having something like this is bad enough without making it even more geeky. 
  • Reply 7 of 11
    macxpressmacxpress Posts: 3,858member
    jume said:
    I wonder where are now all the fan boys that stated this would be the most stupid idea for Apple to implement and would destroy user experience?

    Thanks god for users complaining, law suits filling. Result, better UI control and experience. Well done Apple. 
    Oh don't worry, I'm sure you'll find something else to bitch about with this afterwards. I also think this is a stupid idea, but Apple's hands are kinda forced at this point. We'll see where this goes afters its released for a while. I'm sure people will turn this off and then bitch about their phone shutting down all the time and Apple broke their phone, etc, etc. Another lawsuit coming! 
  • Reply 8 of 11
    Mike WuertheleMike Wuerthele Posts: 1,908administrator
    jume said:
    I wonder where are now all the fan boys that stated this would be the most stupid idea for Apple to implement and would destroy user experience?

    Thanks god for users complaining, law suits filling. Result, better UI control and experience. Well done Apple. 
    Because it remains a stupid idea for Apple to implement. Again, like I've said, perhaps not for "us" meaning the very small minority of Apple customers that read AI -- but for the Apple-using public as a whole? Still really dumb for the reasons articulated above.

    And, re-read the commenting guidelines, conveniently linked at the bottom of the page. Your opinions are important, but be mindful of how you express them.
    edited February 7
  • Reply 9 of 11
    tipootipoo Posts: 788member
    "iPhone 8, iPhone 8 Plus, and iPhone X models include hardware updates that allow a more advanced performance management system that more precisely allows iOS to anticipate and avoid an unexpected shutdown."

    Does this mean the 7 and prior have a 'dumb' method of determining when to throttle, like cycle count instead of precise battery age, while the 8 forward rely on precise shutdown conditions?

    This is a question that should be answered too, batteries have a lot of luck and variation in care associated with them, one mans 500 cycle shutdown-prone battery may be another womans 500 cycle 90% fine battery.
    atomic101
  • Reply 10 of 11
    tipootipoo Posts: 788member
    I'm going to be very interested to see what this looks like on mine. 

    My iPhone 7 is under a year old, even with a full cycle a day it should be far from the 500 they rate them at before hitting 80% capacity, but it drops frames everywhere around the UI and is rather frustrating that way. I can't tell yet what's iOS11 and what's the battery. 
  • Reply 11 of 11
    tipoo said:
    "iPhone 8, iPhone 8 Plus, and iPhone X models include hardware updates that allow a more advanced performance management system that more precisely allows iOS to anticipate and avoid an unexpected shutdown."

    Does this mean the 7 and prior have a 'dumb' method of determining when to throttle, like cycle count instead of precise battery age, while the 8 forward rely on precise shutdown conditions?

    This is a question that should be answered too, batteries have a lot of luck and variation in care associated with them, one mans 500 cycle shutdown-prone battery may be another womans 500 cycle 90% fine battery.
    I made a similar comment when my SE was in a steady state of 50% throttling.  My theory is that for the "older" phones (I.e. not iPhone 8 or X), Apple’s throttling algorithm is more simplistic, looking mainly at things like battery age and cycle count. I had not been experiencing any random shutdowns or other behavior prior, and the throttling became noticeable only when I upgraded to iOS 11. 

    So essentially, in order to be cautious and to CYA, Apple’s initial throttling procedure was very aggressive and ended up blanketing batteries that may have otherwise been perfectly fine. 

    Since replacing my battery two weeks ago, performance is consistently at 100% speed and runs like butter. 
    tipoo
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